site: Updated the "Building Jackrabbit" page to mention the binary releases.
site: Updated the "Building Jackrabbit" page to mention the binary releases.

git-svn-id: 02b679d096242155780e1604e997947d154ee04a@437198 13f79535-47bb-0310-9956-ffa450edef68

apache/jackrabbit,apache/jackrabbit,apache/jackrabbit